The disclosed embodiments relate to subsurface irrigation systems for supplying fluids to the root region of plants.
The term “irrigation” is understood to be the supplying of fluids, in particular water and/or nutrient solutions, to plants. To irrigate plants, water can be applied to the soil and the plants from above. In order to minimize water loss, the water can be applied in the vicinity of the individual plants by spray devices or drip devices. However, such spray and drip devices still suffer from water lost, such as through evaporation, wind drift, overspray, and excessive run off.
These disadvantages can be avoided if irrigation systems are used that are placed underground in the soil beneath the plants. Such irrigation systems include irrigation mats that are equipped with irrigation tubes, which are connected to the water supply system by means of valves and control units.
The use of subsurface irrigation continues to increase in residential and commercial landscaping, horticulture, green houses, and agriculture. This is because subsurface irrigation can provide significant savings in water usage as compared to conventional irrigation while simultaneously leading to higher yields in agriculture and to healthier plant growth in landscaping and horticulture.
Subsurface irrigation is an important step to avoid unnecessary overspray, runoffs, damaged walkways and walls, calcified windows, and the like. Further, subsurface irrigation may allow the reusing of rain-, storm- or recycled water for irrigation purposes because it may keep odors underground and may keep such water away from direct contact with humans or animals such as pets.
DE 695 14 365 T2 has disclosed a capillary irrigation system of this kind, which has an irrigation mat that is equipped with a plurality of perforated irrigation tubes. The irrigation mat is composed of an upper layer of a capillary material and a lower layer of a capillary material, between which the irrigation tubes are situated. The terms “above” and “below” relate to the orientation of the irrigation mat when placed in the soil.
To accommodate the tubes, pockets are provided between the two layers of capillary material, formed by folding the upper layer. The preformed pockets are dimensioned so that the irrigation tubes can be slid into the pockets. The two layers are attached to each other, for example by means of gluing, sewing, ultrasound, or welding. The attachments here are seam-like connections, which have the disadvantage that, for example, sewing threads can break and the attachment points can come loose. The placement of such mats is then significantly more complex due to the slippage of the individual layers. Since such mats have edge lengths of 50 m or more, not only does this impede the handling and laying of the mats, but the tubes can also slip laterally and assume positions other than those provided. A uniform distribution of water in the irrigation mat is no longer possible in this case.
Further, when using a mat where layers are threaded together, the installation time and labor required is very high. Cutting threads requires specific tools, and even then the individual threads tend to get stuck in the tools. Further, the threads may be cut loose from the layers when they are cut by the tools, further weakening the connection between layers.
Some subsurface irrigation system utilize subsurface emitters. While subsurface emitters may reduce evaporation to provide more efficient irrigation, they create another problem. This is that the roots of the plants tend to grow into the exit openings of the emitters. This can result in the emitters becoming clogged and, in the worst case scenario, completely blocking the exit of water. This impairs efficient and uniform water distribution in the subsurface irrigation system.
Subsurface irrigation like other systems may be highly dependent on the soil structure. Sandy soils or soils which do not disperse fluids laterally require higher amounts of water to achieve the watering needs of the plant, seedling, crop, or grass. Thus the water savings expected from subsurface irrigation may become lower than expected. Often costly replacement soil is brought in to resolve this. Pointed drip irrigation may also frequently fail when the plant, seedling, or shrub is not placed correctly close to the emitter and dies or receives the water only partially. This may also be true of subsurface irrigation where not all of different types of plants may receive the water from the subsurface irrigation equally. That is, different types of plants may have different planting depths which are not equally served by the subsurface irrigation system.
Typical subsurface irrigation also tends to be configured at a uniform depth over a large area. In some applications, such as desert landscaping, this may be superfluous and may also fail to meet the needs of different, adjacent, landscaping features. Further, such features may require different planting depths and spacing between them.
Typical systems involving prior irrigation mats may also not be compatible with the use of storm water or grey water. This is because specialized tubing with certain markings and specifications must be utilized for storm water or grey water. Thus, subsurface irrigation systems that can effectively incorporate storm or grey water are desired.